Transcript for Mystery at Sea: Missing Yacht Sailing From New Zealand to Australia

And now, vanished. Tonight, authorities serging for answers to a mystery at sea. A crew of seven, six of them american, sailing on a big yacht from new zealand to australia. They are missing. Abc's dan harris now has the giant waves and the total silence. Good morning, america. This is david dyche on the "hu "hunter nina." Reporter: This is the captain of the nina, an 85-year-old wooden schooner, during happier times -- a transatlantic CROSSING IN THE 1990s. Tonight, though, david dyche is lost at sea with his wife, their teenage son and a crew of four othepeople. The last time anyone spoke to them was on june 3rd as they traveled from northern new zealand to australia. A 73-year-old crew member named evi used a satellite phone to call a meteorologist in new zealand and said, the weathes turned nasty. How do we get away from it. The meteorologist advised her to head south and brace for the storm. The next day he got a text reading, "any update for nina?" Evi. And that was the final communication. We know the conditions at that moment were terrible. 68-mile-an-hour winds, 26-foot waves. But david dyche has navigated rough seas before. Things deteriorated even further to a point that we weren't able to handle the vessel, it was so windy. He's been a ship captain all his life. I have hope, you know, I mean, hope is our lifeline, as I said. Reporter: Officials say it's possible that the crew lost communication and drifted off course. Or that they're now on lifeboats. But air force search planes have scoured the seas but so far nothing. Dan harris, abc news, new york.

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